1. Field of the Invention
The present invention concerns a control unit of a valve mechanism, which has an electromagnetic coil.
2. Description of Prior Developments
Control units for electromagnetically operable hydraulic valves are encountered ever more frequently in technology, particularly in antilock systems in the automotive industry. A particular faculty of application of the said control unit exists in the automotive industry in antilock systems (ABS) and antiskid devices. In order to control the various systems, the control unit monitors, for example, the skid behavior of the wheel of a passenger vehicle. If, for example, there is a risk that the wheel might lock during the process of braking, this is detected by sensors on the wheel and transmitted to the control unit; to this control unit are linked several electromagnetically operable hydraulic valves. These valves are arranged in units (valve blocks) and in order to avoid situations in the vehicle which can no longer be controlled, the control unit controls the brake circuit in such a way that before a wheel locks, the force of braking is reduced by means of bringing about the opening and closing of the hydraulic valve, until the danger of a wheel lock has been removed.
The valve blocks, which consist of several electromagnetic valves have, as a rule, a valve reception body, a housing, as well as a cover for closing the housing. The housing has openings for the reception of the contact pins of the electromagnetic coils, which are located in the housing. These contact pins are fastened directly to the printed circuit boards, which transmit signals for the control of the hydraulic valves.
It is important in the case of such control units that the complete control unit should be shielded from outside influences, so that good sealing of the said unit is ensured during assembly. In doing so, the fitting of the housing on the valve block presents problems, because only very small tolerances are available for the fastening and connection of the coils to the electronic printed circuit boards.
DE 37 42 320 A1 describes a valve block with several electromagnetically operable hydraulic valves, which has a cover with electrical conductors and conductor strips made from brass sheet and located in the said cover, the conductors being fitted with contact elements which, on the cover being fitted on the valve block, are brought into contact with the contact elements of the electromagnetic valve coils.
U.S. Pat. No. 5,374,114 describes an electro-hydraulic pressure control (device with several electromagnetically operable hydraulic valves where the coils are flexibly arranged flexibly on a carrier via an elastic plastic fixing device.
A drawback of the aforementioned state-of-the-art resides in the fact that an elastic suspension of the coils is needed for the state-of-the-art control unit and that the holes in the housing cover for the reception of the coil contacts to the printed circuit boards exhibit play, making the said opening difficult to cover.
It is accordingly the purpose of the present invention to make possible the economical and simple construction of a control unit for a tightly sealable valve mechanism, whilst conserving large tolerances.
According to the present invention, this purpose is accomplished by the fact that the electromagnetic coil is connected electrically and mechanically to the control unit via a connection device, which has at least one spring-mounted connecting ridge.
This has the advantage that during assembly, that is to say during the fitting of the housing containing the electronic unit on the hydraulic unit via the spring-mounted connecting ridge, a greater degree of clearance is possible. The electrically conducting spring-mounted connecting ridge serves to compensate axial and radial forces when the coils are connected to the control unit, that is to say, when the housing is fitted on the hydraulic unit. The connecting ridge serves simultaneously as an electrical contact for connection to the printed circuit board and for the compensation of inaccuracies in manufacture.
For improved spring action, the spring-mounted connecting ridge can have a first undulating sector, which is arranged between a wire connection sector and a contact sector. Furthermore, the connecting ridge can be arranged substantially at right angles to the axis of the electromagnetic coil where the contact pin lies parallel to the axis of the coil.
In this way, clearance during manufacture can be increased in the direction of insertion of the contact pin.
To achieve a greater degree of stiffness of the spring-mounted connecting ridge, the connection device can have an insulating ridge, which supports the connecting ridge and where the insulating ridge has a second undulating sector. This insulating ridge increases the stiffness of the spring-mounted connecting ridge.
Furthermore, the connecting ridge can be fitted to a coil end. The contact pin and the connecting ridge can substantially lie at right angles to one another.
Furthermore, the coil can have a spool holder with collars, where the connecting ridge has a first step, which is cast into one of the collars.
Furthermore, the insulating ridge can be a part of the collar and project beyond the latter, where the insulating ridge has a first area enclosing the first step and a second area formed around a second step where the second undulating sector connects the first area with the second area.
Furthermore, the contact ridge and the contact pin can be connected with one another via a sealing shoulder. This sealing shoulder makes it possible to seal the control unit after the housing has been pierced by the contact pin.